• Elastomers and Composites
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• 제54권1호
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• pp.61-69
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• 2019

Poly(ethylene-co-vinyl acetate) (EVA) is a copolymer of ethylene and vinyl acetate (VA). It is important to determine the VA content of EVA, since the properties of EVA depend highly on the VA content. EVA copolymers have been used in a wide range of applications appropriate for the different VA contents. IR, NMR, and TGA are generally used for determination of the VA content of EVA copolymers. Of these, TGA is the most reliable method and can be applied to cured EVAs. Analytical methods for determination of the VA content and properties of EVA copolymers via TGA were herein reviewed. Thermal behaviors of EVA copolymers (glass transition temperature ($T_g$), melting point ($T_m$), and crystallization temperature ($T_c$)) determined by DSC were also reviewed. Analysis of the related literature revealed that the $T_g$, $T_m$, and $T_c$ decrease by about 0.46, 1.36, and $2.08^{\circ}C$, respectively, for every 1 wt% in VA content. A method for determining the degree of crosslinking of cured EVA copolymers was also reviewed, and the degree of crosslinking tends to increase with the decrease in the VA content.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.63-64
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• 2003

As a part of a research on the development of polymeric textile finishing agents, polymerization of low molecular weight copolymers containing maleic anhydride residues have been studied. In order to obtain low molecular weight poly(maleic anhydride-co-vinyl acetate) copolymers, the feed ratio of the two monomers and the concentrations of initiator and chain transfer agent were varied in the copolymerization. The copolymers were characterized using GPC, NMR, FTIR, DSC, and TGA. Copolymers with molecular weights in the range 2,150 to 6,630 have been prepared and characterized. The hydrolysis of the anhydride groups of the copolymer in water is also discussed.

• 한국염색가공학회지
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• 제3권2호
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• pp.43-48
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• 1991

Cellulose acetate (CA) and poly-4-vinyl pyridine (PVP) in various weight proportions were mixed in a mixed solvent of trifluoroacetic acid: methylene chloride/6:4 (v:v). CA was miscible with PVP in that solvent system. CA/PVP/solvent show liquid crystal in a certain range of concentration and the nature of that liquid crystal was cholesteric. Films of the liquid crystal composite cast from the liquid crystal solutions of CA/PVP were tested in a viewpoint of biomembrane. Results show that considering permselectivity CA/PVP membrane is better than that of CA and CA/PVP membrane is closer to cell membrane.

• 한국인쇄학회지
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• 제12권1호
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• pp.1.2-15
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• 1994

This is the study which appear the relation between the situation of Anchor point and the qualities of lithographic prints using the uncoated paper. Anchor point were measured by microscopic photography and Kubelka-munk`s method. The situation of Anchor point increased with print density and print though, but it decreased with evenness and rub off. In case of commercial uncoated paper, the situation of Anchor point was optimized when it was 25~35% apporoximately. In preparation of samples for microscopic photography, the samples were used by the resin testing methods. This method used that the resin fixes the printed papers of sample very hard, in preparation of samples for microscopica potography a good result could be gained by this method.

• Fibers and Polymers
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• 제5권2호
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• pp.105-109
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• 2004

The synthesis of titanium dioxide nanofibers with 200-300nm diameter was presented. The new inorganic-organic hybrid nanofibers were prepared by sol-gel processing and electrospinning technique using a viscous solution of titanium isopropoxide (TiP)/poly(vinyl acetate) (PVAc). Pure titanium dioxide nanofibers were obtained by high temperature calcination of the inorganic-organic composite fibers. SEM, FT-IR, and WAXD techniques were employed to characterize these nanofibers. The titanium dioxide nanostructured fibers have rougher surface and smaller diameter compare with PVAc/TiP composite nanofibers. The anatase to rutile phase transformation occurred when the calcination temperature was increased from $600^{\circ}C$ to $1000^{\circ}C$.

• Elastomers and Composites
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• 제51권1호
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• pp.63-67
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• 2016

Poly(ethylene-co-vinyl acetate) (EVA) was pyrolyzed to eliminate acetic acid of VA unit using off-line pyrolysis, and the deacetylated EVA was analyzed infrared spectroscopy (IR) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). EVA film for deacetylation was prepared by solution casting on aluminum foil and it was pyrolyzed at low temperature of $300^{\circ}C$ in the off-line pyrolysis apparatus. After deacetylation, carbon-carbon double bond (C=C) was formed by 1,2-elimination of the VA unit in the EVA backbone. Most of C=C bonds were trans-1,4-unit and 1,2-unit was also observed. Presence of the 1,2-unit in deacetylated EVA indicates that terminal or branch VA units exist in the raw EVA. Py-GC/MS chromatogram of deacetylated EVA displayed much smaller acetic acid and much more abundant other pyrolysis products than that of raw EVA, which means that the pyrolysis efficiency and separation condition were improved.

• 폴리머
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• 제28권2호
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• pp.128-134
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• 2004

비타민E 아세테이트를 봉입하고 있는 셀룰로오스 나노입자는 개선된 자발적 유화확산 방법을 이용하여 제조하였다. 셀룰로오스 나노입지는 셀룰로오스 유도체와 비타민E 아세테이트를 아세톤/에탄올 혼합유기 용매로 용해한 다음 초음파 발생장치를 이용하여 폴리(옥시에틸렌 솔비탄 모노올레이트) 용액에 분산하여 제조하였다. 입자크기와 비타민 E 아세테이트의 봉입률은 광산란 장치와 UV 분광계를 이용하여 각각 측정하였다. 나노입자의 안정성은 상온에서 30일간 입자크기 변화를 통해 비교하였고 입자의 형태는 주사전자 현미경을 통해 관찰하였다. 결과적으로 제조된 나노입자의 형태는 구형인 것을 관찰하였고, 상온에서 30일간 입자크기 변화가 없었다. 가장 좋은 셀룰로오스 나노입자의 제조 조건은 1% w/v 니트로셀룰로오스와 8% w/v 폴리(옥시에틸렌 솔비탄 모노올레이트)를 사용하였을 경우이고, 이때 나노입자의 크기는 65nm, 비타민E 아세테이트의 봉입률은 71%의 값을 나타내었다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.48-51
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• 2003

Poly(vinyl alcohol) (PVA) obtained by the saponification of poly(vinyl ester) like poly(vinyl acetate) or poly(vinyl pivalate) is a linen. semicrystalline polymer, which have been widely used as fibers for clothes and industries, films, membranes, medicines for drug delivery system, and cancer cell-killing embolic materials[1-3]. PVA fibers and films have high tensile and compressive strengths, high tensile modulus, and good abrasion resistance due to its highest crystalline lattice modulus. (omitted)

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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• pp.104-107
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• 2003

Poly(vinyl alcohol) (PVA) obtained by the saponification of poly(vinyl ester) like poly(vinyl acetate) o. poly(vinyl pivalate) is a linear semicrystalline polymer, which has been widely used as fibers for clothes and industries, films, membranes, medicines for drug delivery system, and cancer cell-killing embolic materials[1-3]. PVA fibers and films have high tensile and compressive strengths, high tensile modulus, and good abrasion resistance due to its highest crystalline lattice modulus. (omitted)

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2017년도 정기학술대회 발표논문집
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• pp.213-213
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• 2017